Method for preparing masked images



Aug. 19, 1958 K. E. WHITMORE 2,848,326

METHOD FOR PREPARING MASKED IMAGES Filed Sept. 26, 1955 Fig.

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AT70/P/VEY & AGE/VT United States Patent C) METHOD FOR PREPARING MASKED HVIAGES Keith E. Whitmore, Rochester, N. Y., assignor to Eastman Kodak Company, Rochester, N. Y., a corporation of New Jersey Application September 26, 1955, Serial No. 536,502 8 Claims. (Cl. 96-44) This invention relates to photography and more particularly to a method for making masked images which on printing give greatly improved reproductions.

It is well known in the art of photography that when it is desired to obtain reproductions of images on transparent supports it is customary to merely print through the image onto a suitable light-sensitive photographic element and thus a reversed image is obtained, for example, a positive image from a negative transparency. Occasionally, it is found that the resultant image lacks the desired photographic quality-that is, the contrast, tone, image sharpness, etc. of the print is diiferent or degraded as compared to the original subject. A common method for correcting the above kind of defects in reproductions includes the making of a separate masking image, generally a thin lowcont-rast positive if printing from a neg-a tive transparency, registering the resultant mask with the transparency, and then printing the final reproduction through the combination. Since separate masks are difiicult to register accurately in proper contact with the original transparencies, it would be very desirable to provide a photographic element containing as an integral part thereof materials capable of forming on exposure and development appropriate masks which are permanently and accurately registered within the element.

I have now found that improved light-sensitive photographic elements and transparencies therefrom of the above desired kind can be readily prepared by superimposing on a suitable support separate colloid layers, one of which contains a colored coupler capable of coupling with the oxidation product of certain primary aromatic amine developing agents and is free of silver halide, and another of which is a silver halide emulsion layer free of coupler and separated from the above layer containing the colored coupler by a relatively thin colloid interlayer such as a gelatin layer. The colored coupler layer is preferably next to the support followed by the gelatin interlayer and over this the silver halide emulsion layer. This is the preferred photographic element for practicing the invention. However, the reverse order of these layers on the support is also operable. The silver halide emulsion layer can be sensitized to any desired wave length.

When a photographic element as above described is processed according to the method of my invention, I have found that the transparency obtained contains in the colored coupler layer a diffuse or unsharp mask image which functions in a printing operation to increase the contract in microstructure relative to extended area, and also acts to improve the overall image sharpness of the reproduction. The thickness of the gelatin interlayer is a functionof the degree of unsharpness which should be corrected in the principal image, i. e. the thicker the layer the more diffuse or unsharp is the masking image formed and may vary from 1 to 15 microns for use with fluorescent screens in radiography to zero (no gelatin interlayer) for use with sharp images as may be encountered in documentary work. For use as an ordinary the exposed element to a silver image by the use of an ordinary black and white developer solution containing,

- for example, hydroquinone, N-methyl-p-aminophenol sulfate or a combination of these compounds followed by rinsing, fixing and washing. The element is then'rehalogenated, for example, in a bath containing an alkali met-a1 ferricyanide and alkali metal bromide. At this point, no marked dye image has been formed. The rehalogenated element is then redeveloped in a solution containing a substituted phenylene diamine type of color developer such as N ethyl N-(p-methanesulfonamidoethyl)-3- methyl-4-aminoaniline or N-ethyl-B-methanesulphonamidoethyl-4-aminoaniline and similar developers which are described in U. S. Patent No. 2,193,015, dated March 12, 1940, of A. Weissberger, or such as N-diethyl-p-phenylene diamine, Z-aminod-diethylamino toluene, etc. and salts thereof, and containing also a substantial amount of a hydroquinone sulfonic acid or an alkali metal salt thereof. The processed element now contains both a negative silver image in the upper layer and in the bottom layer a negative magenta or cyan dye image. Where the colored coupler employed is such that the negative dye image is soluble, it can be washed out leaving only unchanged coupler which constitutes in this situation a positive yellow or orange colored masking image. In the redevelopment step, it appears that the color developer in the developing solution acts in the silver image area to reduce the silver halide to silver and thereby becomes oxidized; (2) the oxidized color developer is then reduced by the hydroquinone sulfonate and the latter thereby becomes oxidized; (3) the oxidized hydroquinone sulfonate and the reduced coupler developer then diffuse through the gelatin interlayer to the bottom layer containing the colored coupler where (4) the oxidized hydroquinone sulfonate oxidizes the reduced color developer in the presence of the colored coupler and (5) the oxidized color developer then couples with the colored coupler to form the dye image. However, it is also possible to obtain the negative masked image by direct color development.

The processing steps for obtaining suitable masked positive images with the described photographic elements ofthe invention require a reversal type of process, but the exposure to the subject is the same regardless of whether the processing is to be negative or reversal. After exposure, with or without suitable color filters, the element is developed to a silver image by use of an ordinary black and white developer solution containing, for example, hydroquinone, N-methyl-p-aminophenol sulfate or a combination of these compounds followed by hardening, bleaching, clearing, flashing, color developing with the previously mentioned phenylene diamine type of color developers, and final washing and drying. The processed element now contains both a positive silver image in the upper layer and in the bottom layer a positive magenta or cyan dye image and an unsharp negative colored coupler image. The formation of the dye masking image is believed to take place in similar manner as previously described for preparing the mentioned masked negative images.

It is, accordingly, an object of my invention to provide a new light-sensitive photographic element which on exposure and processing gives improved masked nega tive and positive images that can be used for superior reproductions. for preparing such masked images, more particularly negative masked images. Another object is to provide a developing solution containing a color developer and a substantial amount of a hydroquinone sulfonic acid or salt thereof. Other objects will become apparent hereinafter.

In the accompanying drawings, which further illustrate my invention, Figs. 1A, Band C and 2A, B and G are enlarged, diagrammatic cross-sectional views of lightsensitive photographic elements before and after processing according to the method of the invention.

Fig. 1A shows an element comprising a support 10, a layer 11 attached thereto and containing a yellow or orange colored coupler capable of coupling with the oxidation products of certain primary aromatic amine developing agents to form magenta or cyan colored dyes but containing no silver halide, and a gelatin silver halide emulsion layer 12 superimposed over said layer 11 and containing no coupler compound. The emulsion employed for layer 12 may be one having the usual amount of contrast and capable of being developed to a density range of about 3.0.

Fig. 1B shows the element of Fig. 1A after exposure to a subject and complete processing to a masked negative image, the layer 12 now containing a negative silver image 14 and containing no silver halide, and layer 11 now containing a relatively unsharp negative magenta or cyan dye image 15 and a relatively unsharp positive yellow or orange colored coupler image 15a formed by the unchanged colored coupler, in register with the negative silver image 14.

Fig. 10 shows the element of Fig. 1A after exposure and complete reversal processing to a masked positive image, the layer 12 now containing a positive silver image 16 and containing no silver halide, and layer 11 now containing a relatively unsharp positive magenta or cyan dye image 17 and a relatively unsharp negative yellow or orange colored coupler image 17a formed by the unchanged colored coupler, in register with the positive silver image 16.

Fig. 2A shows an element similar to that of Fig. 1A, except that a relatively thin gelatin layer 13 is interposed between layers 11 and 12.

Fig. 2B shows the element of Fig. 2A after exposure and complete processing to a masked negative image, the layer 12 now containing a negative silver image 18 and containing no silver halide, and layer 11 now containing a relatively difiuse or unsharp negative magenta or cyan dye image 19 and a relatively unsharp positive yellow or orange coloredcoupler image 19a formed-by the unchanged colored coupler, in register with the negative silver image 18.

Fig. 2C shows the element of Fig. 2A after exposure and complete reversal processing. to a masked positive image, the layer 12 now containing the positive silver image 20 and containing no silver halide, and layer 11 now containing a relatively unsharp positive magenta or cyan dye image 21 and a relatively unsharp negative yellow or orange colored coupler image 21a formed by the unchanged coupler, in register with the positive silver image 20.

If in above Figs. 1 and 2, the coupler yields a soluble dye, the cyan and magenta images represented by 15, 17, 19 and 21 wash out in processing and leave only the silver and diffuse unchanged colored coupler images 15a, 17a, 19a, and 21a.

Suitable colored couplers which couple with the oxidized color developer to give mask dye images include compounds such as the following:

I. 1 hydroxy 4 (2 amyloxycarbonyl 3 naphthylazo -N- 8-3 -sulfobenzamido) ethyl] -2'-naphthamid e,;

Another object is to provide a method 0 ONHCHrCHzNHC 0 i M C OzCsHu-normal This coupler is orange colored and inthe process of the invention it couples with the diffused oxidized color developer to give a soluble cyan dye image. it may be prepared by heating phenyl-l-hydroxy-Z-naphthoate with an excess of ethylene diamine to give the intermediate naphthol compound which is then reacted with rn-chlorocarbonylbenzene sulfonyl chloride, ClCO-C H -SO Cl, in the proportions of two equivalents of the naphthol intermediate to one equivalent of the acid chloride, the amine hydrochloride being separated by filtration. The filtrate is drowned in water and the precipitate collected. This is then refluxed in a 50-50 water and alcohol solution, the excess alcohol removed and the aqueous residue filtered. The filtrate is chilled and the produce collected which has the structure:

. C ONHCHiGHaNHC 0- soar The above product (-A) is then coupled in a basic medium such as pyridine, sodium hydroxide or acetic acid plus sodium acetate with 2-amyloxycarbonyl-3- naphthalene diazonium chloride (prepared by reacting 2-amino-3-naphthoic acid with n-amyl alcohol, followed by diazotization) to give the colored coupler I.

II. 1-phenyl-3-(3-sulfobenzamido)-4 (4 octadecyloxyphenylazo) -5-pyrazolone some tii N=NOO CiaHsv This coupler is yellow colored and in the process of the invention it couples with the ditfused oxidized color developer to give a soluble magenta dye image. It may be prepared by heating two equivalents of l -phenyl-3- amino-S-pyrazolone with one equivalent of m-chlorocarbonylbenzene sulfonyl chloride, ClCO-C H -SO Cl, to form the corresponding acid chloride, followed by hydrolysis of the acid chloride to the free sulphonic acid in a 50-50 water and alcohol hydrolysis medium, and then coupling in a basic medium suchas pyridine, sodium hydroxide or acetic acid plus sodium acetate with p-octadecyloxybenzene diazonium chloride to give the colored coupler II.

III. l-phenyl-3-(2-carboxybenzamido)-4 (4-dodecyloxyphenylazo) -5 -pyr azolon e:

-on ii lien-Ge on,

This'coupler is yellow colored and in the process of the invention it couples with the diffused oxidized color developer to give an isoluble magenta dye image. It may be prepared by heating on a. steam bath a mixture of 1-ptert,-butylphenoxyphenyl-3 amino 5 pyrazolone with alpha-(p-tert. butylphenoxy) propionyl chloride, isolating the amide derivative and then coupling it with pmethoxybenzene diazonium chloride in a basic medium such as pyridine, etc. to give the colored coupler IV. The preferred colored couplers are the compounds III and V.

Other broadly similar colored couplers of the type of above I include 1 hydroxy-N-[B-(3-sulfobenzamido) ethyl] -4- (Z-dodecyloxyphenylazo) -2-naphthamide, i-hydroxy-4-(2-dodecyloxycarbonylphenylazo)3,5' -di carboxy-Z-naphthamide, l-hydroxy-N 3 (3,5-disulfbenzamido)ethyl]-4-(2 dodecyloxycarbonylphenylazo) 2 naphthamide, 1-hydroxy-4-(2-dodecyloxycarbonylphenylazo)-2-(4-sulfonaphthanilide), 1-hydroxy-4-(2-amyloxycarbonyl-3-naphthylazo)-N-[l8 (2 carboxybenzamido)- ethylJ-Z-naphthamide, and the like.

Suitable hydroquinone sulfonic acids and salts thereof include hydroquinone monosulfonic acid and lithium, sodium, potassium, etc. salts thereof and, hydroquinone disulfom'c acid and mono and dilithium, sodium, potassium, etc. salts thereof. The disulfonates are preferred and particularly potassium hydroquinone disulfonate. The amount of the hydroquinone sulfonic acid compound that is employed in the color developer solution can vary widely, but ordinarily from about 50-200% of the weight of the color developer contained therein is etficacious.

The following example illustrates further the method of practicing my invention.

Example 1 A photographic element as above described was prepared by first coating a subbed transparent cellulose acetate support of about 0.005" thickness with a gelatin solution in water containing 5.5 g. per 100 cc. of the yellow colored coupler 1-phenyl-3 (2 carboxybenzamido) -4- (4-dodecyloxyphenylazo -5-pyrazolone, designated III above, but containing no silver halide, to a dried thickness of approximately 4 microns, .followed by coating thereover a 5% gelatin solution in water to give a gelatin dried layer approximately 8 microns in thickness, and over this was coated a gelatino-silver bromide emulsion containing no colored coupler and having a cured thickness of approximately 8 microns. The photographic element thus prepared was then exposed to a subject and processed to a masked negative image. The processing solutions and the steps of the process are described in the following:

Processing solutions:

First developer solutionp-Methylaminophenol sulfate. 2.0 grams. Sodium sulllte (desiccated) 90.0 grams. Hydroquinone 8.0 grams. Sodium carbonate (monohydrate) 52.5 grams. Potassium bromide 5.0 grams.

Water to make up to a volume of 1 liter. Second developer solution- Benzyl alcohol 4 co. in 800 cc. of

water. Sodium sultite (desiccated) 2 grams. N ethyl N (B methanesulionamidoethyD- 6.0 grams 3-methyl-4-aminoanl.line.

Potassium hydroquinone disulionate 2.5 grams. Sodium carbonate (monohydrate).... 50 grams. Sodium hydroxide 0.5 grams Water to make up to a volume of 1 liter.

Rehalogenating solution Potassium ierricyanido... 50 grams. Potassium bromide 20 grams. Water to make up to a volume of 1 liter.

Fixing solution Sodium thiosuliate 240.0 grams Sodium sulfite (desiccated)...

Potassium alum Water to make up to a volume of 1 liter. Hardener solution- Potassium chrome alum 30 grams. Water to make up to a volume of 1 liter. Processing steps:

Developing time (first developer) 3 mins. at 70 F. Rinsing time 5 sec.

Fixing time 5 mins Washing time. 5 mins Hardening time 3 mins Washing time. 5 mins Rehalogenizing 2 mins Washing time 15mins.

Color and mask developing time (second de- 20mins.

velopor).

Washing 5-10 mins.

Dry.

The resultant masked negative contains a negative silver image in the upper layer and, since the magenta dye masking image which forms is soluble, it washes out leaving a positive, diffuse yellow image of the unreacted colored coupler in the lower layer adjacent to the support. The masked negative was then printed through a suitable filter onto a fine grain positive film to give on processing a greatly improved positive print as compared with prints obtained with similar unmasked negative transparencies. The desired degree of masking may be controlled by the color of the printing filter.

Ex'ample 2 A photographic element prepared as described in Example 1 was exposed to a subject and processed to a masked positive image by a reversal process. The processing solutions and the steps of the process are described in the following:

Processing solutions:

First developer solution- Potassium thiocyanate 2.0 grams. p-Methylamiuo phenol su1iate 2.0 grams. Sodium sulfite (desiccated) 90.0 grams. Hydroquiuone 8.0 grams. Sodium carbonate (monohydrate)- 52.5 grams. Potassium bromide 5.0 grams. Water to make up to a volume o! 1 liter.

Hardener solution- Potassium chrome alum 30.0 grams. Water to make up to a volume of 1 liter.

Bleach Solution- Potassium dichromate Ammonium sulfate Sodium sulfate Sulfuric acid (conc.) Water to make up to a volume of 1 liter.

Clearing so1ution Sodium carbonate (monohydrate). 30.0 grams. Sodium sulflte (desiccated) 30.0 grams. Water to make up to a volume of grams.

n Sodium carbonate (monohydrate) 50.0 grams. Sodium hydroxide 0.5 gram,v Vtqafietr to make up to a volume of The resulting masked positive image contains a positive silver image in the upper layer and, since the magenta dye masking image which forms is soluble, it washes out leaving a negative, diffuse yellow image of the unreacted colored coupler in the lower layer adjacent to the support.

Masked positives prepared as described in above Example 2 have special uses. For example, a normal negative may be duplicated and masked at the same time by making use of the described reversal process. Another example is in the preparation of radiographs. As is known, radiographs are customarily viewed and read as negatives. Reversal processing yields a masked positive which will give the conventional radiographic negative in one printing operation. Here also the degree of masking may be controlled by the color of the printing filter.

In the above examples, the photographic element can be substituted by other generally similar elements of the invention. For example, the thickness of the gelatin interlayer can be varied from zero to 12 microns. Also, the colored coupler in the lower layer can be replaced by a like amount of any other of the mentioned colored couplers of type I or II which likewise contain solubilizing groups and give similar masked negative and positive images. When the colored coupler of the above example is replaced by a colored coupler of the type IV, which contains no solubilizing groups, the masked image obtained also contains an insoluble diffuse magenta image. The cellulose acetate film support can also be replaced by other cellulose 'cstcrs such as cellulose propionate, cellulose acetate-propionate, cellulose acetatebutyrate, etc., by synthetic resins such as polyvinyl acetal, poly esters, etc., by glass and other transparent supporting materials. In special cases a translucent or opaque material can also be used such as paper, metal and the like. The gelatin in the layers may also be replaced by other colloid materials such as polyvinyl alcohol, cellulose carboxylatcs, agar-agar, etc., but gelatin is the preferred colloid material.

In the above example, the processing solutions can also be replaced with equivalents. For example, the First Developer in the examples can be substituted with either of the following developing compositions:

Water to make up to a volume of 1 liter.

while in the Second Developer in each of the examples, the N-ethyl N-(13-methanesulfonamidoethyl)-3-rnethyl-4- aminoaniline color developer can be substituted, for example, with a like amount of N-diethyl-p-phenylene diamine, or with Z-aminod-diethylamino toluene hydrochloride or with N-ethyl-N-(p-methanesulfonamidoethyl)-4-aminoaniline. Likewise, the potassium hydroquinone disulfonate can be substituted in the second de- 8 veloper in each of .the examples, with a like amount of any of the mentioned hydroquinone sulfonic acidsand derivatives, for example, with sodium hydroquinone'disulfonate, or with lithium hydroquinone disulfonate or with hydroquinone disulfonic acid to give similarly advantageous masked negatives and positives for reproduction, purposes.

What I claim .is:

1. The method of making a masked negative image in a photographic element including a support material and three separate colloid layers superimposed thereon, one of which is adjacent to the support material and contains a colored coupler capable of coupling with the oxidation product of at least one N-alkyl substituted phenylene diamine developing agent and is free of silver halide, another of which is a gelatin interlayer having a thickness of from 1 to microns, and the other of which is over the said interlayer and is a gelatino-silver halide emulsion layer free of coupler, comprising exposing said element to an image, developing said element with a phenolic developing agent to form a negative silver image in the said emulsion layer, fixing and rehalogenating said element to remove unexposed silver halide and to convert the said silver to silver halide, and then redeveloping the said rehalogenated element with a solution containing an N-alkyl substituted phenylene diamine developing agent and an alkali metal hydroquinone disulfonate to reform the negative silver image in the said emulsion layer and to form a negative dye image in the said layer containing the said colored coupler.

2. The method of making a masked negative image in a photographic element according to claim 1 wherein the said alkali metal hydroquinone disulfonate is potassium hydroquinone disulfonate.

3. The method of making a masked negative image in a photographic element according to claim 1, wherein the said colored coupler is 1-hydroxy-4-(2-amyloxycarbonyl-3-naphthyla'zo)-N-[{3 3 sulfobenzamido)ethyl] Z-naphthamide and wherein the said alkali metal hydroquinone disulfonate is potassium hydroquinone disulfouate.

4. The method of making a masked negative image in a photographic element according to claim 1, wherein the said colored coupler is l-phenyl-3-(3-sulfobenzamid-o)-4 (4 octadecyloxyphenylazo) 5 pyrazolone and wherein the said alkali metal hydroquinone disulfonate is potassium hydroquinone disulfonate.

5. The methohd of making a masked negative image in a photographic element according to claim 1, wherein the said colored coupler is 1-phcnyl-3-(Z-carboxylbenzamido)-4 (4-dodecyloxyphenylazo) 5 pyrazolone and wherein the said alkali metal hydroquinone disulfonate is potassium hydroquinone disultonate.

6. The method of making a masked negative image in a photographic element according to claim 1, wherein the said colored coupler is 1-(p-tert.-butylphenoxy)- phenyl-3-a-(p tert. butyl phcnoxy)propionylamino- 4-(p-methoxyphenylazo)-5=pyrazolone and wherein the said alkali metal hydroquinone disulfonate is potassium hydroquinone disulfonate.

7. The method of making a masked positive image in a photographic element including a support material and three separate colloid layers superimposed thereon, one of which is adjacent to the support material and contains a colored coupler capable of coupling with the oxidation product of at least one N-alkyl substituted phenylene diamine developing agent and is free of silver halide, another of which is a gelatin interlayer having a thickness of from about 1 to 15 microns, and the other of which is over the said interlayer and is a gelatino-silver halide emulsion layer free of coupler, comprising expcs ing said element to an image, developing said element with a phenolic developing agent to form a silver image in the said emulsion layer, bleaching out the said silver image from the said emulsion layer, exposing the bleached 10 said alkali metal hydroquinone disulfonate is potassium hydroquinone disulfonate.

References Cited in the file of this patent UNITED STATES PATENTS 2,306,410 Schinzel Dec. 29, 1942 2,397,452 White Mar. 26, 1946 FOREIGN PATENTS 503,824 Great Britain Apr. 11, 1939 

1. THE METHOD OF MAKING A MASKED NEGATIVE IMAGE IN A PHOTOGRAPHIC ELEMENT INCLUDING A SUPPORT MATERIAL AND THREE SEPARATE COLLOID LAYERS SUPERIMPOSED THEREON, ONE OF WHICH IS ADJACENT TO THE SUPPORT MATERIAL AND CONTAINS A COLORED COUPLER CAPABLE OF COUPLING WITH THE OXIDATION PRODUCT OF AT LEAST ONE N-ALKYL SUBSTITUTED PHENYLENE DIAMINE DEVELOPING AGENT AND IS FREE OF SILVER HALIDE, ANOTHER OF WHICH IS A GELATIN INTERLAYER HAVING A THINKNESS OF FROM 1 TO 15 MICRONS, AND THE OTHER OF WHICH IS OVER THE SAID INTERLAYER AND IS A GELATINO-SILVER HALIDE EMULSION LAYER FREE OF COUPLER, COMPRISING EXPOSING SAID ELEMENT TO AN IMAGE, DEVELOPING SAID ELEMENT WITH A PHENOLIC DEVELOPING AGENT TO FORM A NEGATIVE SILVER IMAGE IN THE SAID EMULSION LAYER, FIXING AND REHALOGENATING SAID ELEMENT TO REMOVE UNEXPOSED SILVER HALIDE AND TO CONVERT THE SAID SILVER TO SILVER HALIDE, AND THEN REDEVELOPING THE SAID REHALOGENATED ELEMENT WITH A SOLUTION CONTAINING AN N-ALKYL SUBSTITUTED PHENYLENE DIAMINE DEVELOPING AGENT AND AN ALKALI METAL HYDROQUINONE DISULFONATE TO REFORM THE NEGATIVE SILVER IMAGE IN THE SAID EMULSION LAYER AND TO FORM A NEGATIVE DYE IMAGE IN THE SAID LAYER CONTAINING THE SAID COLORED COUPLER. 